Add Access Environment Variables Native Image demo

Author: olyagpl

.github/workflows/access-environment-variables.yml

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+name: native-image/access-environment-variables
+on:
+  push:
+    paths:
+      - 'native-image/access-environment-variables/**'
+      - '.github/workflows/access-environment-variables.yml'
+  pull_request:
+    paths:
+      - 'native-image/access-environment-variables/**'
+      - '.github/workflows/access-environment-variables.yml'
+  schedule:
+    - cron: "0 0 1 * *" # run every month
+  workflow_dispatch:
+permissions:
+  contents: read
+jobs:
+  run:
+    name: Run 'native-image/access-environment-variables'
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    strategy:
+      matrix:
+        java-version: ['21', '24-ea']
+    steps:
+      - uses: actions/checkout@v4
+      - uses: graalvm/setup-graalvm@v1
+        with:
+          java-version: ${{ matrix.java-version }}
+          distribution: 'graalvm'
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          native-image-job-reports: 'true'
+      - name: Run 'native-image/access-environment-variables'
+        run: |
+          cd native-image/access-environment-variables
+          ./run.sh

native-image/access-environment-variables/.gitignore

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+.class
+envmap

native-image/access-environment-variables/EnvMap.java

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+import java.util.Map;
+
+public class EnvMap {
+    public static void main (String[] args) {
+        var filter = args.length > 0 ? args[0] : "";
+        Map<String, String> env = System.getenv();
+        for (String envName : env.keySet()) {
+            if(envName.contains(filter)) {
+                System.out.format("%s=%s%n",
+                                envName,
+                                env.get(envName));
+            }
+        }
+    }
+}

native-image/access-environment-variables/README.md

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+# Access Environment Variables in a Native Executable at Runtime
+
+You can find the steps to run this demo on [the website](https://www.graalvm.org/latest/reference-manual/native-image/guides/access-environment-variables/).

native-image/access-environment-variables/run.sh

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+#!/usr/bin/env bash
+set -ex
+
+$JAVA_HOME/bin/javac EnvMap.java
+$JAVA_HOME/bin/native-image -Ob EnvMap
+
+./envmap HELLO
+export HELLOWORLD='Hello World!'
+./envmap HELLO